The present invention relates generally to the field of LED lighting systems. More particularly, embodiments of the present invention relate to circuits and methods for a switching power supply for driving an LED lighting system.
As energy demand increases, an imbalance exists in the demand and supply of energy sources. With cost of energy continuing to rise, energy-saving green technology is becoming increasingly important. As an example, the energy consumption in lighting systems can be as high as 20% of the total energy consumption. Therefore, energy efficient light systems can have a big impact in reducing energy consumption.
In particular, LED (light-emitting diode) lamps have the advantages of high efficiency, small volume, and the ability to provide a single light color. As a result, LED lamps have found wide applications in lighting and backlight applications.
The ability to adjust the brightness of a lighting system enables the user to tailor the lighting system to the need of a particular environment that can result in substantial savings in energy costs. Conventional techniques in adjusting the brightness often use a dimmer circuit, which removes either the front portion in the input voltage AC (alternate current) cycle, as in leading-edge dimmers, or the rear portion in the input Ac cycle, as in trailing-edge dimmers.
However, in lighting systems, it has been challenging to control the brightness of lighting systems based on different light sources. As described above, LED lamps have many advantages, but without proper voltage supply and precise current control, the efficiency and heat consumption of an LED lamp can suffer, leading to shortened life time. It is especially changing to use dimmers with an LED lamp.
Therefore, improved brightness control in LED light systems is highly desirable.